Milling machine



Sept. 5,1933.

c. D. OESTERLEIN El AL 1,925,599

MILLING MACHINE- 9 Sheetsl-Sheet 1 Filed April 1, 1929 INVENTORS WAQflWW k m ATTORNEY5 p 5, 1933- c. D. OESTERLEIN ET AL I 1,925,599

MILLING MACHINE 9 Sheets-Sheet 2 Filed April 1, 1929 INVENTO Rf BY a 7-W MM ATTORNEYS P 1933. c. D. OESTERLEIN EI'AL ,599

MILLING MACHINE Filed April 1, 1929 9 Sheets-Sheet 5 VERT/CALALVUSTMENTINVENTOR W ATToRN EY p 1933- 'c. D. OESTERLEIN ETAL 1,925,599

MILLING MACHINE Filed April 1, 1929 9 Sheets-Sheet 4 W BY W v ATTORNEY5Sept- 5, 1933- c. D. OESTERLEIN ET AL MILLING MACHINE Filed April 1,1929 9 Sheets-Sheet 5 INVENTOR ATTORN EYS Sept. 5, 1933. c. D.OESTERLEIN ET AL MILLING MACHINE Filed April 1, 1929 9 Sheets-Sheet 6lNVENTOBj p c. D. OESTERLEiN ET AL 99 MILLING MACHINE Filed April 1,1929 9 Sheets-Sheet 7 M w H a, 4 W m H z 1 yaw x W L 2 5 J, 1M 1 H M I NM: 6 \\V// 1 0 \M w. 1 z P M I 2 g; 4 I I K v 1 1 .M. A M 4\ w 5 g H 9 rT\ s \\\\\s I -I i. f a a y 1 ,3 I flJ 1 w 9 7 9 v 9 ll! w a 1 Sept. 5,1933. c. D. OESTE RLEIN ET AL MILLING MACHINE Filed Ap ril l, 1929 9Sheets-Sheet 8 Q (SP/NDL 5 10; w H n g 1 1 I 11 M F I INVENTOR WK m Asml j Se t. 5, 1933. c. D. OESTERLEIN ET! AL 5,

MILLING MACHINE Filed April 1-, 1929 9 Sheets-Sheet 9 Patented Sept. 5,1933 FICE BIILLING MACHINE Charles D. Oesterlein and Charles F.Littelmann,

Cincinnati, Ohio, assignors, by mesne assignments, to Washington Bankand Trust Comp ny, Ohio Cincinnati, Ohio,

a corporation of Application April 1, 1929. Serial No. 351,498 8 Claims.-(oi. -20) f-his invention'rleates to a processommethod ofsimultaneously and continuously machining or milling a plurality ofparts or pieces of work for high production capacities, and to theapparatus therefor.

The method consists in mounting a plurality of parts or pieces of workin a consecutive order upon a continuously revolving support and about alarge central revolving cutter mounted ec-. centrically or ofiset to thecircular or elliptical path or traverse of the work, the parts or workmoving gradually into the path of the cutter teeth and for a portion oftheir orbital or elliptical path to the full depth of cut, the relativecutter rotation and rotative traverse of the work being at differentrates, and the depth of cut regulated by the distance the cutter isoffset.

The finished parts in their traverse move clear of the cutter, whencethey may be unloaded by hand or mechanical ejector devices and replaced.The cutting or milling zone assumes a crescent form, starting into thework at zero to full depth, and leaving at zero to the relief of thecutter teeth, the action being substantially free from chatter.

An ample portion of the work traverse about the cutter is left outsidethe milling zone in which unclamping, unloading, reloading, andreclamping can be executed, and in which the rotation or travellingmotion of the work can be utilized for unclamping and reclamping.

The apparatus employed for practicing the method embodies a circularrevolving work table witha revolving milling cutter centrally thereofand adjustable-to present the cutter either eccentric or' concentricwith or to the axis of the revolving work table and in its eccentriccapacity applicable for continuous multiple milling. The work table andcutter occupy an inclined position,

. with the milling zone at a rear side fully housed or enclosed,enabling the-use of a high volume and pressure of coolant flow directedagainst the cutter and work for washing the cuttings and chips from theinclined table and at its lowest elevation, allowing the work to drainas it moves in an upwai'd grade, permitting the same to efficientlydrain as it moves into the loading zone.

The transmission mechanism for both the spindle and table is carriedwithin bearings below the plane of the table and provides for a simplemassive drive from below, and of ample strength and rigidity, adequateto any torsional stress of the heaviest cuts to be .encountered. It alsopermits of a centralized system of lubrication, a r

of movement and after the full depth of cut or compact arrangement ofparts, easily accessible, and the controlling and adjusting hand leversat the front side of the machine, conveniently accessible to theoperator.

The cutter being positioned centrally of the table enables the use of anincreased diameter of table for holding a large number of parts or workholding fixtures and the use of an unusually large diameter of spindle,short and heavy, journalled in substantial bearings, and is journalledwithin a vertically adjustable slide journal mounted upon a transverselyadjustable headstock, adapting the spindle to be vertically andlaterally adjusted.

An object of the invention is to provide a method for simultaneously andcontinuously milling a plurality of parts or pieces of work for highproduction capacity,

Another object is to provide a method of constant milling characterizedby useful employment of the maximum portion or number of teeth of amilling cutter within the milling field of the cutter revolution, and bythis increase inanilling field or zone providing that a great number ofparts may be constantly and simultaneously milled within the increasedzone, resulting in high production capacity.

Another object of this invention is to provide a method for millingwherein the work continuously moves in an endless path about a rotatingcircular cutter, the work gradually moving into the path of the cutterand correspondingly receding therefrom during a portion of its pathfinished milling is reached to completely clear 90 the cutter forreplacement, and wherein the rotative work traverse is utilized foractuating work holding fixtures to unclamp and clamp the work withoutmilling interruption.

Another object of the invention is to provide a large central circularrevolving cutter set eccentric or ofiset to a work carrying table,adapting the parts mounted upon the table to travel with rotation of thetable in an endless path engaging the cutter during a portion of itstraverse, gradually intercepting the cutter to the full depth of cutteror degree of milling, and thence receding correspondingly therefrom, tocompletely free the parts for removal and replacement during thecontinuous rotation of the table.

Another object of the invention is to provide a milling machine which bythe offset arrangement of the cutter relative to the Work circle affordsa coarser cut in the early stages of the milling, the depth of cutdiminishing as the work moves through the milling zone and easing off toan infinitely fine cut at the conclusion of the operation, whereby aburr is prevented.

,Another object of the invention is to provide a machine for milling aplurality of parts simultaneously and at relatively diiferent degreesfrom the time of starting the out until the finished depth is reachedand in proportion to the degree or regulated distance that the cutter isoffset or eccentric to the path of travel of the work, for presenting anincreased number of cutter teeth in action or engaged with the work at atime, maintaining a relatively constant working load upon the spindle,eliminating chatter.

Another object of the invention is to provide a revolving milling cuttercentrally of a revolving table with the journals and driving gears belowthe plane of the table providing a compact and sturdy structureoccupying a minimum floor space, the table and cutter horizontallydisposed and at an elevation-from the fioor conveniently accessible tothe operator for removing and applying the work to the fixtures carryingthe work, and also for applying and removing the cutter.

Another object of the invention is to provide a milling machine with thejournals and gearing for supporting and rotating the table and spindlehoused within oil-tight compartments below the elevation of the tablefor centralized lubrication.

Other features and advantages of the invention relate to structuraldetails and arrangement of parts, all of which will be more fully setforth in the description of the accompanying drawings, in which: I

Figure 1 is a perspective view of the milling machine, with the workholding clamps removed from the revolving table.

Figure 2 is a top plan view.

Figure 3 is a section on line 3-3,.Figure 2.

Figure 4 is a fragmentary section through the bed and transmissionmechanism journalled and housed within the bed.

Figure 5 is a sectional view taken on line 5-5, Figure 3.

Figure 6 is a rear elevation of the overhead bracket supporting themotor with an idler pulley for the driving belt shown in section.

Figure '7 is a sectinon taken on line 7-7, Figure 4.

Figure 3 is a section on line 8-8, Figure'l.

Figure 9 is a section on line 9-9, Figure 8.

Figure 10 is a section on line 10-10, Figure 3, illustrating therevolving table in top plan, with a plurality of work holding fixturesand pieces of work clamped to the table.

Figure 11 is a section on line 11-11, Figure 10.

Figure 12 is a sectional view taken on line 12-12, Figure 2.

Figure v13 is a diagrammatic plan view of the table, work, and cutter.

Referring to the drawings, 1 indicates the bed of the machine organizedas a hollow casing for journalling. and supporting a revolving spindlecarrying the milling cutter and a work table revolving about the cutter,the cutter and work table revolving in relatively reverse rotation andthe spindle and work table relatively adjustable for positioning thesame either eccentric or concentrio. The work is clamped upon the tableabout the spindle for continuous milling.

The spindle and revolving work table are indicated as rotated in counteror reverse directions and at relatively different rates by transmissiongearing journalled and housed within the bed, producing a compactorganization easily accessible to the operator. It will be understood,however, that the cutter and table may revolve in the same direction atrelatively different rates. if desired. The spindle and work table arepref erably set askew, presenting the table in an inclined positioninclining downwardly rearwardly so that the coolant and chips can bedrained and carried rearwardly into the base of the bed or a pan-shapedportion of the casing above the bed, avoiding the necessity of theoperator brushing the parts to keep the same clean during millingoperations. The spindle and work table, however, may be set inhorizontal instead of tilted.

The upper portion 2 of the casing is of pan shape fixed upon the bed andsurrounds the table. for confining the chips and coolant within themachine. The rear portion 3 of the casing is arched, providing a supportfor an electric motor 4 having a pulley 5 in belt transmission with adriven pulley 6 of the gearing journalled within the bed of the machine.

The casing presents a design of unique appearance, open for the upperforward portion for convenient access to the table for clamping the workthereon either manually or automatically, and closed for the rearportion, completely covering the work and cutter in the milling zone.The bearings for the spindle, table, and transmission gearing,therefore, are housed below the work holding surface of the table onlubricant tight casings or compartments for-efiicient or constantlubrication.

It has been experienced that a circular revolving table is highlyadaptable for continuous milling, the table moving continuously in aforward direction, and with the tiltingform of table there is noopportunity for the piling up of the chips upon the table. The millingis primarily performed within a rear section so'that the chips andcoolant are easily delegated or drained from the lowermost elevation ofthe table.

In utilizing a single milling cutter centrally of a plurality of piecesof work clamped in a circular order upon the work table, the work movesin an orbital pathabout the cutter, so that each piece is consecutivelypresented to the cutter and gradually to the action of the cutter from astarting out to the fullest depth of cut, from whence the work movesgradually away and out of reach of the cutter, to be removed or replacedby another piece.

The work, therefore, for each revolution of the tablemoves within whatmay be termed a loading zone and thence within a milling zone, and inpassing from one zone to the other is automatically unclamped or clampedwhen free of the cutter.

A large milling cutter in an offset capacity relative to the work hasits teeth out of engagement for a suificient length of time to preventthe v cutter from being unduly heated. Large diameter cutters make itpossible to use large spindles and arbors, adding rigidity to thespindle struchandle for manually relatively opposite sides thereof,giving the -for- Ward side a dovetail formation for slidably seatinginto the V-way or channel of a column or headstock 13 slidably supportedin the underhung dovetailed gib or slideways 13 on the lower side of thepan casing 2. The slide journal 9 is rigidly clamped to the headstock byhand operated clamping devices carried by the headstock at relativelyopposite sides of the journal slideway (see Figures 8 and 9).

' The clamping devices are the duplicate of one another, each comprisingan eccentric shaft 14 vertically journalled in the headstock having apair of eccentrics 15-15, each eccentric engaged through a clamp block16 slidably supported in a bore in the headstock transverse to theeccentric shaft. The block 16 has a bolt 17 secured thereto and extendedthrough an elongated slot 18 in a lateral flange 19 integral with andextending approximately radially from the slide journal 9, the head ofthe bolt 17 bearing against a cap plate 20 upon the outer side of theflange 19 covering the elongated slots 18. Turning the eccentric shaftin appropriate directions moves the slide blocks 16 in either ofalternate directions, clamping the journal 9 rigidly tothe headstock orreleasing the same.

Each eccentric shaft at its lower end has a bevel gear 21 fixed thereonin mesh with a bevel gear 22 fixed upon the end of a shaft 23 journalledin the forwardly projectingwing 24 of the headstock, the shaft extendingthrough the forward upper end of the bed for access at the forward sideof the machine. The forward end of the shaft 23 is squared for thereception of the crank rotating the shaft to operate the clamps.

The spindle is vertically adjusted to change the elevation of the cutterrelative to the plane of the table by a screw 25 journalled in theheadstock, at the forward side of the journal 9 and in threadedengagement through a nut element or ear 26 projecting from and integralwith the journal 9.

The lower end of the adjusting screw 25 has a bevel gear 27 fixedthereon in mesh with a bevel gear 28 fixed on the rear end of a shaft 29journalled in the forwardly extended wing 24 of the headstock andextends for access at the front side of the machine. The forward end ofthe shaft is squared for applying a hand crank for manual shaftrotation. Gauge devices 30 are provided at the forward end of the shaft29 for indicating the degrees of the spindle adjustment.

The spindle 7 extends beyond the slide journal 9 and through anelongated hub 31 of the worm wheel 32, to which the spindle is splined.The hub 31 extends concentrically through a bushing 33 having anannularly flanged lower'end fixed to the headstock, with its oppositeend telescopically engaged into the lower end of the slide jour-- nal 9.The hub 31 rests upon a bearing washer 34 interposed between the faceside of the hub and upper end of a hub extension 35 of the closure cap36 secured through the lower end of the headstock. The hub 35 of the capprovides a housing and bearing for a pair of roller bearings 37-37engaged upon a bushing 38 splined on a counterturned lower end of thespindle.

The cap plate 36 is provided with a stuffing box cover 39 concentricallyabout the lower end of the spindle closing and sealing the bearingchamber formed by the hub 35.

The bore of the spindle at itshead end is tapered to receive acorresponding tapered shank of a cutter carrying arbor 40, the arborbeing locked to the spindle by a tie rod 41 threaded into the taperedend of the arbor and projecting through the bore of the spindle and inthreaded engagement through a bushing nut 42 socketed into the lower ortail end of the spindle. The spindle head is provided with a collar 43annularly engaged with a flanged end of the spindle capping over theupper endof the slide journal 9 to provide a cover for the bearingchamber intermediate the spindle and journal, the collar 43-v beingengaged by the packing 44 interposed between the collar and upper end ofthe journal 9 to provide a lubricant sealing joint.

A circular cutter 45 is keyed upon the arbor 40 at an appropriateelevation above the surface of the table and secured against lateralaxial displacement by a lock nut 46 screw-threaded upon the arbor andspacing collars 47 disposed at opposite sides of the cutter. The upperorfree end of the arbor 40 is journalled and slidable in a steady restor bracket 48 adjustably mounted upon the arch portion 3 of the casingand preferably centrally thereof and at one side of the motor supporting bracket 49 bolted upon the casing.

The headstock, as shown in Figures 5 and 12, is slidably mounted in ways13 l3 at relatively opposite sides of the headstock and underhung fromthe lower side of the pan-shaped casing 2, and is adjusted or moved inthe ways for positioning the spindle either concentric with therevolving work table or at varying degrees eccentric thereof. Theheadstock (see Figure 3 is adjusted by a screw 50 engaged through a nut51 fixed upon the forwardly projecting wing portion of the headstock,with the forward end of the screw journalled in a bearing 52 at theforward end of the casing 2 centrally of the machine. The forward end ofthe screw is squared for the reception of a hand crank, and is alsoprovided with indi cator devices 53.

The revolving table 54 is in the form of'an annulus, with its uppersurface provided with cir 'cular and radial T-slots for securing thework holders upon the table about the cutter. The lower side of thetable is provided with a conical hub 55.journalled within acorrespondingly tapered'bearing 56 fixed upon the base of the easingportion 2. Lubricant distributing means 57 for supplying lubricant tothe bearing surface of the table are shown as leading forwardly of thein a fill cup within operator.

A worm Wheel 58 is fixed to the end of the hub of thetable in mesh witha worm sleeve'59 splined upon a cross shaft 60, the shaft 60 journalledin bearing bushings 6161 at opposite ends of the worm sleeve 59, thebushings being suitably mounted in bearings or supports 62 as a part ofthe base of the pan-shaped casing 2 and at the lower side thereof. Endthrust roller bearings 63 are interposed between the ends of the wormsleeve 59 and bearing bushings 61.

The shaft 60 is slidable longitudinally for engaging and disengaging itsclutch end 64 with a corresponding clutch end 65 of shaft 66. A handlever 67 pivoted'to a bearing bushing68 is engaged into an annularshifter spool 69 fixed on the shaft for actuating the shaft. The bearingbushing 68 is engaged and socketed into the side of the casing 2 andprovides a bearing for the end of the shaft 60, and the end' of theshaft 60 is squared for the reception of a crank handle.

The shaft 66 is journalled within a bearing bushing mounted in'a sidewall of the casing 2, the shaft carrying on its outer end a gear 70 as amember of change gear transmission housed within the transmissioncompartment 71 of the casing 2, the transmission compartment havingaclosure cap '72 covering an opening through the casing outer wall.

The change gear transmission connects with a train of gearing housedwithin a second compartment 73 of the casing 2 and in connection-withthe gear 74 on a shaft 75 journalled in bearings in the bed portion ofthe machine. The Shaft 75 is driven by the pulley 6 fixed upon the endof the shaft, the pulley being in connection with the driving pulley ofthe motor through a belt 76.

The driving belt 76 is tightened by means of an idler pulley 7,6journalled on a bracket 76 slidably mounted in a slideway in the sideface of the support 49. An adjustment screw 76 is screw-threaded intothe support l9, longitudinally entering the slideway and engaging withthe slidable bearing support 76 for adjusting the same, the adjustmentscrew having a nut thereon for permanently setting the idler pulley inposition.

Various forms of transmission may be instituted between the driven shaft75 and the driven shaft (H) or worm sleeve 59 for rotating the table,the particular system of gearing herein employed constituting a gear 77suitably journalled in hearings in the bed and in mesh with the gear 74fixed on the drive shaft 75. The gear 77 in turn is in mesh with a gear78 within the transmission compartment 73 as a member of a compoundgear. The second gear 78 of the compound is in mesh with a gear 79 on ashaft 80 extending from the transmission compartment 73 into theadjacent transmission compartment 71 and carries a second gear 81 inmesh with a gear 82 as a member of a compound change gear, the secondmember 83 of the compound meshing with the gear 70 on shaft 66. Thecompound gear is supported upon a swinging lever or quadrant 84 suitablysupported.

A bevel gear 85 is fixed upon the inner end of the main drive shaft 75in mesh with a bevel gear 86 splined upon the end of a shaft 87 (seeFigure 5). Ihe shaft 87 extends forwardly and into a transmissioncompartment 88 in the front end of the headstock and moveslongitudinally with the headstock in the lateral adjustment of thespindle.

A gear 90 is fixed upon the end of the shaft 37 within the transmissioncompartment 88 in mesh with a gear 91 likewise housed within thetransmission compartment 88 fixed upon the forward end of a shaft 92extending longitudinally with the shaft 87. The shaft 92 carries a wormsleeve 93 splined thereon and in mesh with the worm wheel 32 of thespindle. The various shafts are suitably journalled in roll or ballbearings to which detail description need not be made.

Likewise, arrangement is made for complete lubrication of the bearingsand gearing by housing the same in oil-tight casings and cornpartmcnts.

The spindle be adjusted relative to the axis of the work table withoutdisturbing the transmission connection and while the transmission is inmotion due to the splined connection of shaft 87 with the bevel gear 86,and for vertical adjustment of the spindle due to the splined connectionof the spindle with the worm wheel.

For increased production capacities and continuous milling, the table isprovided with a plurality of automatically actuated work holders or workclamps adapting the pieces of work to be quickly clamped or unclampedwith the continued rotation of the table, the continued rotativefunction of the table utilized for actuating clamp controlling deviceslocated within a suitable loading zone of table rotation at which thework is clear of the cutter.

The milling job is accomplished within a single revolution of the table,and the work is engaged or in action with the revolving cutter duringonly a portion of each revolution of the cutter. The work in eachrevolution from a loading zone is gradually presented to the action ofthe cutter teeth and correspondingly retreats therefrom. allowing ampleopportunity for removing a finished piece and replacing it with anotherwhile the table continues its rotation.

The pieces of work are arranged upon the table in a consecutive circularorder, the path being eccentric to the axis of the cutter, and the tablebeing of comparatively large diameter allows for a large number ofduplicate pieces to be mounted thereon. The method is more easilycomprehended upon reference to the diagrammatic view, Figure 13, whichillustrates the table equipped with twenty-one pieces of work 94,equally spaced apart and in a circular row. eccentric to the axis of thecutter, the degree of eccentricity governing the depth of cut or degreeof milling. In the diagrammatic view, a spacing is shown between theopposite ends of the row of work, designated as a loading zone, andmerely as indicative of an area within the convenient access of theoperator, at which the work is unclamped and free to be removed by theoperator and replaced with another. In actual operation this spacingdoes not appear, the parts being equally spaced from each other aroundthe entire circumference of the table.

The work or portion milled or to be milled is indicated as a cylindricalor circular part or portion which is shaded to show the degree ofmilling when presented to the action of the cutter and when finished."Thus, the first three pieces to the left of the loading zone space inthe figure are free from to be in the clamping zone. The next ninepieces are within the milling zone. The next five pieces are retreatingfrom the cutter, the milling having been finished, and the followingfour out of reach of the cutter and within what may be termed theunclamping zone.

Thus, nine pieces are continuously and simultaneously operated upon foreach revolution of the table, giving an idea of the milling orproduction capacity under this method. The number of pieces of work hasbeen merely arbitrarily selected, the parts passing to the path of thecutter in a planetary manner and have to travel through a third of aturn of the table in adtancing far enough toward the center of thespindle, so that the cutter reaches the bottom of the cut. This istquivalent to feeding the parts directly toward the spindle, the exactdepth of the cut. 1

Facilities are provided for automatically clamping and unclamping thework as they aptures. I

proach the loading zone and depart therefrom, so that the operator needsonly to remove the unclamped piece and replace the same with another.Various types of work holding fixtures can be employed, and in theinstance herein ilpermits the fixtures to be mounted as a unit,

facilitating assembly of fixtures taking a particular piece of work andin substituting one type of fixture for another upon the table.

A piece of work 94 represented as a cylindrical block is set within theV-notch of the stock, the stocks arranged in pairs for holding twopieces of work simultaneously clamped by a single clamping deviceconsisting of a pair of clamp plates 98--98 pivotally suspended from aconnecting plate 99, the clamping plates respectively engaging upon apiece .of work set in one of the stocks. The connecting plate 99 isengaged by a clamp rod or bolt 100 having a slide block 101 fixed to itslower end slidably engaged within a bore in the base plate and engagedby a laterally moving wedge rod. 102 slidably sustained within the baseplate 96 for depressing the clamp rod and releasing the same forclamping and unclamping the work. I

The inner end of the wedge rod is inclined and extends through a slot inthe slide blocklOl which is correspondingly inclined, as shown in Figure11, and when the rod'is forced inwardly the clamp rod is drawndownwardly,- bringing the clamp plates upon the work, rigidly holdingthe same within the stocks. The forward end of the wedge rod is providedwith a transverse groove 103 for engagement with a stationary cam 104extending from a bracket plate 105 rigidly bolted to the machine casingor other suitable stationary support, the cam causing the withdrawal ofthe wedge rod as the rod in its traverse with the rotating table movesinto cooperation with the cam.

The wedge rod as it leaves the loading zone is moved inwardly by a pushlever or dog 106 pivotally mounted upon a bracket or support 107 as astationary support. The dog or lever is springpressed so asto yieldunder undue resisting pressure against. the inward movement of the rodwhen its full wedging force is exerted for the required clampingpressure upon the work. This .provides a safety feature and allows forvariations in clampingpressures of the several fix- The operator isstationed at the front side of the machine for removing the unclampedfinished pieces of work within the loading zone and replacing the sameby a second to be machined.

The speed of operation is only limited by the ability of the operator toremove and insert the work without stopping or starting the machine ortable rotation.

A round revolving table lends itself admirably for the automaticoperation of work clamped at definite points in each revolution of thetable and operative through the rotative motion of the table.

In the particular arrangement and tilting form of table, the milling isaccomplished at the rear side of the machine completely housed by thecasing of the machine, away frpm the operator, and permits the supply ofa coolant of a high pressure and volume discharged from a nozzle 110directed against the cutter and work rear- 'part approaches the bottomor end of cut, the feed wardly, the coolantwashing the chips from thework and table into the reservoir portion of the pan-shaped casing, andthe inclination of the table allows ample drainage of coolant from thework and table as it passes out of the milling zone and into theunclamping zone. The lubricant is fed tothe nozzle 110 from the base ofthe machine by means of a pump 111 mounted on the side of the machineand'driven from the main driving pulley 6 by means of a belt 112.

The larger the cutter the larger will be the milling range or zone,consequently allowing for more parts to be mounted within the range forsimultaneous operation thereon.- With many teeth of a large cutterengaged with the work at one time, the more constant is the braking loadon the machine. This results in a very smooth movement of the cutterblades at-all stages of a revolution. In the use of small diametercutters with only one or a few teeth engaged at a time the effect is asuccession of hammer blows, and to speed up production the cutter mustbe run at high rates of speed.

Under the present method, new parts are constantly presented to thecutter, requiring no change in feeding rate from starting out tofinishing, and high production rate is obtained without cramming thefeed to the detriment of the cutters. There is no shifting or cuttingoif of the coolant for there is no idling or travel to position forsuccessive milling. There is constant variation .in cut from the time ofstarting on one piece to the time of finishing it, the out beingextremely coarse in the early stage of the milling and'steadily reducedin an approximate geometric progression to zero or a very fine out atthe end of the operation.

It frequently occurs that the length of cut is heaviest at the base of agroove being milled as where there is a groove being formed partlythrough a circular part (see Figure 10), and the advantage of having thecut extremely fine at the end of the operation will be apparent.

From the diagram it will be seen that as a gradually tapers off to zero,where the two circles become tangent, from which point the work beginsto recede from the cutter. Inmilling steering spindles and similarparts, this arrangement is of particular advantage.

The machine is adapted for small face milling jobs, slotting, straddlemilling, and to some extent form milling.

Having described our invention, we claim:

1. A milling'machine, comprising a bed, a ringform rotary work holdingtable journalled in said bed, transmission gearing for rotating thetable, a headstock, constituting a column portion. and a base portion,the base portion slidably supported in the column, said headstockadjustable radially of the axis of the table, aslide journal in saidcolumn portion of the headstock, and a spindle journalled in said slidejournal for axial adjustment with said slide journal, and transmisaiongearing for rotating said spindle.

2. A milling -machine, comprising, a frame, a table mounted on saidframe; said table having a conical hub seating in a conical opening insaid frame, a ring form worm wheel hung from said table, a transmissionfor driving'said gear and table, a headstock slidably mounted in themounted in the-upper end of said carrie a driving transmission for saidspindle, and means for adjusting said headstock radially of the centerof said table for offsetting the tool carrier relative to said center.

3. In a milling machine, a frame, a table journalled in said frame, atransmission for rotating said table, a headstock mounted below saidtable, a spindle extending upwardly from said headstock and disposedcentrally through said table, said headstock being adjustable on theframe for offsetting the center of the spindle relative to the center ofthe table, a transmission carried by said headstock, said transmissionin driving connection with the transmission driving the table, and meansfor elevating and setting the tool carried by the spindle relative tothe table.

4. In a milling machine, a frame, a table journalled in said frame, atransmission for rotating said table, a headstock mounted below saidtable, a spindle extending upwardly, from said headstock and disposedcentrally through said *table, said headstock being adjustable on theframe for ofisetting the center of the spindle relative to the center ofthe table, and a transmission carried by said headstock, saidtransmission in driving connection with the transmission driving thetable.

5. In a milling machine, a frame, a work-holding table journalled insaid frame, transmission means for rotating said table, a headstockslidably mounted-in the frame below the table for adjusting theheadstock radially of the table and having a spindle support extendingthrough a central opening through the table, a spindle journal slidablymounted upon the headstock for adjustment transversely to the radialadjustment of the headstock, a spindle joumalled in said slide journaland adjustable therewith as a unit, and transmission means joumalled insaid headstock for rotating the spindle.

6. In a milling machine, a frame, a workholding annulus joumalled insaid frame, transmission means for rotating said annulus, a headstockslidably mounted in the. frame below the table for adjusting "theheadstock radially of the table and having a portion extending throughthe work-holding annulus, a spindle joumalled in said headstock, theradial adjustments of the headstock adapting the spindle to the positionconcentric with and eccentric to the axis of said work-holder annulus,and transmission means joumalled in said headstock for rotating thespindle; I

neaaeea diameter to simultaneously mill a number of pieces of work withits cutter teeth relatively concentric and rotating at a higher ratethan the trawersing rate of the work support making a multiple number ofrevolutions in the period a piece of work traverses through a millingzone or for a partial revolution of the work support, and means forrelatively offsetting the cutter and work circle for governing themaximum degree of milling depth of the cutter, the work in moving in anorbit about the cutter, eccentric to the circumference of the cuttertraversing in milling and non-milling zones for each revolution of thework support, the non-milling zone utilized for removal and replacementof the pieces of work.

8. In a machine for continuously milling, a plurality of pieces of work,a rotating work support, one or more work holders mounted upon saidsupport for holding the pieces of work in a consecutive order and theportions thereof to be milledin a common work circle, a rotative spindleand circular milling cutter therefor, the spindle and cutter rotating ata higher rate than the traversing rate of the work support making amultiple number of revolutions in the period a piece of work traversesthrough a milling zone or for a partial revolution of the work support,the cutter having its itutter teeth relatively concentric and as a unitof a diameter to simultaneously operate upon a number of pieces of workas" they are continuously traversed within a milling zone for eachrevolution of the work support, the axis of the work support and millingcutter relatively eccentric, the degree of eccentricity governing themilling depth of the cutter,'the workmoving in an orbit about the cutterand traversing the milling and non-milling zones for each revolution ofthe work support, the non-milling zone utilized for removal and.replacement of the pieces of work.

CHARLES D. OESTERLEIN. CHARLES F. LITTELMANN.

